Numerical simulation of a Trombe wall to predict the energy storage rate and time duration of room heating during the non-sunny periods

In this paper, 2D numerical simulation of the Trombe wall performance and indoor air environment under unsteady state condition for a room located in Yazd, Iran are studied. The governing equations involve mass, momentum and energy conservation, which are discretized by the finite volume method after non-dimensionalization. The SIMPLER algorithm is used for coupling the velocity and pressure. The average absorbed solar radiation on the Trombe wall has been defined for different hours of the coldest period of the year (21 January–19 February) in Yazd. All equations have been solved together using a FORTAN code. The main aim of this research is to investigate the time duration of room heating during the non-sunny periods. The stored energy of the wall being delivered to the inside room was defined for different materials of the Trombe wall. The results show that the Trombe wall made of paraffin wax can keep the room warmer in comparison with other materials for about 9 h.     

The use of 6-carboxynaphthofluorescein phosphoramidite in the automated synthesis of quencher-dye oligonucleotide probes (QDOPs)

Real-time detection and quantitation of specific amplicons have been achieved using quencher and dye-labeled oligonucleotides such as molecular beacons. The molecular beacon molecule has a fluorescent reporter dye at the 5′-end and a quencher at the 3′-end. When the closed molecular beacon is excited by irradiation, the reporter fluorescence is greatly reduced by quenching through the process of fluorescence resonance energy transfer. When the molecular beacon hybridizes to the target, the stem loop opens making the fluorophore and quencher spatially distinct, thus increasing the reporter dye fluorescence intensity. Labeling of dyes to 5′-end of oligonucleotides has been done typically using manual methods, it is possible to do manual coupling at the milligram scale. Described here is the development of a scalable process for oligonucleotide labeling, which is robust, and has been achieved for 6-carboxynaphthofluorescein by connecting it to a corresponding phosphoramidite [Theisen, P.; McCollum, C.; Upadhya, K.; Jacobson. K.; Vu, H.; Andrus, A.; Tetrahedron Lett.1992, 33, 5033-5036].     

Analytical treatments of the space–time fractional coupled nonlinear Schrödinger equations

Under investigation in this work is a (\(2+1\))-dimensional the space–time fractional coupled nonlinear Schrödinger equations, which describes the amplitudes of circularly-polarized waves in a nonlinear optical fiber. With the aid of conformable fractional derivative and the fractional wave transformation, we derive the analytical soliton solutions in the form of rational soliton, periodic soliton, hyperbolic soliton solutions by four integration method, namely, the extended trial equation method, the \(\exp (-\,\Omega (\eta ))\)-expansion method and the improved \(\tan (\phi (\eta )/2)\)-expansion method and semi-inverse variational principle method. Based on the the extended trial equation method, we derive the several types of solutions including singular, kink-singular, bright, solitary wave, compacton and elliptic function solutions. Under certain condition, the 1-soliton, bright, singular solutions are driven by semi-inverse variational principle method. Based on the analytical methods, we find that the solutions give birth to the dark solitons, the bright solitons, combine dark-singular, kink, kink-singular solutions with fractional order for nonlinear fractional partial differential equations arise in nonlinear optics.     

Sub-Angstrom oscillation amplitude non-contact atomic force microscopy for lateral force gradient measurement

We report the first results from novel sub-Angstrom oscillation amplitude non-contact atomic force microscopy developed for lateral force gradient measurements. Quantitative lateral force gradients between a tungsten tip and Si(1 1 1)-(7 × 7) surface can be measured using this microscope. Simultaneous lateral force gradient and scanning tunnelling microscope images of single and multi atomic steps are obtained. In our measurement, tunnel current is used as feedback. The lateral stiffness contrast has been observed to be 2.5 N/m at single atomic step, in contrast to 13 N/m at multi atomic step on Si(1 1 1) surface. We also carried out a series of lateral stiffness-distance spectroscopy. We observed lateral stiffness-distance curves exhibit sharp increase in the stiffness as the sample is approached towards the surface. We usually observed positive stiffness and sometimes going into slightly negative region.     

Lovelock tensor as generalized Einstein tensor

We show that the splitting feature of the Einstein tensor, as the first term of the Lovelock tensor, into two parts, namely the Ricci tensor and the term proportional to the curvature scalar, with the trace relation between them is a common feature of any other homogeneous terms in the Lovelock tensor. Motivated by the principle of general invariance, we find that this property can be generalized, with the aid of a generalized trace operator which we define, for any inhomogeneous Euler–Lagrange expression that can be spanned linearly in terms of homogeneous tensors. Then, through an application of this generalized trace operator, we demonstrate that the Lovelock tensor analogizes the mathematical form of the Einstein tensor, hence, it represents a generalized Einstein tensor. Finally, we apply this technique to the scalar Gauss–Bonnet gravity as an another version of string–inspired gravity. This work was partially supported by a grant from the MSRT/Iran.     

Computer simulation study of the Levy flight process

The random walk simulation of a Levy flight shows a linear relation between the mean square displacement 〈r²〉 and time. We have analyzed different aspects of this linearity. It is shown that the restriction of jump length to a maximum value (l_m) affects the diffusion coefficient, even though it remains constant for l_m greater than 1464. So, this factor has no effect on the linearity. In addition, it is shown that the number of samples does not affect the results. We have demonstrated that the relation between the mean square displacement and time remains linear in a continuous space, while continuous variables just reduce the diffusion coefficient. The results also imply that the movement of a Levy flight particle is similar to the case in which the particle moves in each time step with an average jump length 〈l〉. Finally, it is shown that the non-linear relation of the Levy flight will be satisfied if we use a time average instead of an ensemble average. The difference between the time average and ensemble average results shows that the Levy distribution may be a non-ergodic distribution.     

The effect of solute—membrane affinity on cyclic hydrocarbon—water transport in pressure-driven membrane separation processes

Experimental results for the pressure-driven membrane separation of cyclic hydrocarbons (1,3-cyclohexadiene, cyclohexene, and cyclohexane) from dilute binary aqueous solution using asymmetric cellulose acetate membranes are reported here. In these experiments, total solution fluxes are significantly lower than pure water fluxes at the same applied pressure; this flux reduction is attributed to strong solute—membrane affinity rather than to the osmotic pressure of either the bulk retentate or the boundary layer. An empirical parameter, Z, is used to describe flux reduction. A theoretically based friction parameter, B, is derived assuming the membrane can be represented as an ideal, finely porous membrane; this parameter indicates the influence of solute—membrane affinity on flow through the pores of the membrane. Both the empirical parameter Z and the theoretically based parameter B relate flux reduction to concentrations in the system. Both Z and B increase as solute—membrane affinity increases and decrease as membrane pore size increases. It is concluded that both the empirical flux reduction parameter, Z, and the theoretically based friction parameter, B, indicate the same system properties: solute—membrane affinity and membrane pore size.     

New concepts of regular and (highly) irregular vague graphs with applications

In this paper, some types of vague graphs are introdaced such as $d_m$-regular, $t{d}_m$-regular, $m$-highly irregular and $m$-highly totally irregular vague graphs are introduced and some properties of them are discussed. Comparative study between $d_m$-regular ($m$-highly irregular) vague graph and $t{d}_m$-regular ($m$-highly totally irregular) vague graph are done. In addition, $d_m$-regularity and $m$-highly irregularity on some vague graphs, which underlying crisp graphs are a cycle or a path is also studied. Finally, some applications of regular vague graphs are given for demonstration of fullerene molecules, road transport network and wireless multihop networks.